Got the hydraulic unit rebuilt on the junkyard special super 55. Was full of water but surprisingly little rust. Anyway before teardown the hitch was stuck all the way up because the valve spool had stuck in the raised position. Cleaned everything up, replaced all the seals and O-rings and got it all back together. Now the hitch works great as long as it?s in position control. However if you lower the hitch and flip the leaver under the seat to draft control, it raises the hitch all the way up even though the quadrant handle is still all the way down. Any ideas. It?s a 1955 so it still has the single acting draft system if that makes a difference.